According to this post Multi-pan temporarily disabled | Home Assistant Developer Docs
It is possible to disable multi-pan and reinstall the original Zigbee firmware
But I can’t find any instructions how to reinstall the zigbee firmware. (the post said soon)
Is possible to reinstall the firmware?
Details are here: Flash Silicon Labs radio firmware manually · NabuCasa/silabs-firmware Wiki · GitHub
As a note, this firmware upgrade, as of February 2023, is also available via the web flash utility.
Home Assistant SkyConnect (home-assistant.io)
At this stage you can only flash Zigbee or Multi-Protocol firmware, but inthe future a pure Thread firmware will also be available.
You would ned to put your SkyConnect into the computer you are visiting the website with, and then flash it and reinstall it in your HA instance.